1. Brain’s Building Blocks
Module 3
Brain’s Building Blocks

2. INTRODUCTION Alzheimer’s disease 10% of cases start after age 50
Symptoms:
Problems with memory
Forgetting and repeating things
Getting lost
Being mildly confused

3. INTRODUCTION (CONT’D)
Alzheimer’s disease
Period of 5 to 10 years, symptoms worsen
Result is profound memory loss
Lack of recognition of family and friends
Deterioration in personality
Emotional outbursts
Widespread damage to the brain (hippocampus, involved in memory)
no cure; always fatal

4. INTRODUCTION (CONT’D)
Alzheimer’s disease
Diagnosis and causes
_____________________________________________
Certain chemicals (__________________) that occur naturally in all brains seem to multiply and are believed to cause Alzheimer’s (________________________________)

5. DEVELOPMENT OF THE BRAIN
Fact that your brain doesn’t develop into a nose is because of instructions contained in your genes
Genes
Chains of chemicals arranged like rungs on a twisting ladder
You have about 20,000 to 25,000 genes that contain chemical instructions equaling roughly 300,000 pages of written instructions
Genes program the development of individual parts into a complex body and brain

7. DEVELOPMENT OF THE BRAIN (CONT’D)

8. STRUCTURE OF THE BRAIN Human brain Shaped like a small, wrinkled melon
1,350 grams (less than three pounds)
Pinkish-white color
Consistency of firm Jell-O
Fueled by sugar (glucose)
1 trillion cells divided into
___________________

9. STRUCTURE OF THE BRAIN (CONT’D)
Glial cells
_______________________________________
______________________________________________________________________________________________________________________________

10. STRUCTURE OF THE BRAIN (CONT’D)

11. STRUCTURE OF THE BRAIN (CONT’D)
Neuron
________________________________________
________________________________________________________________________________________________________________________________________________________________________

12. Neuron
Preview Question 1: What are neurons, and how do they transmit information?

13. GROWTH OF NEW NEURONS (CONT’D)
Repairing the brain
Advances in stem research suggest the human brain may be able to grow more neurons
Repair damages due to
accident
disease
Alzheimer’s

14. BRAIN VERSUS MIND Mind-body question:
How complex mental activities such as
feeling
thinking
learning
can be explained by the
physical
chemical
electrical activities
of the brain

15. ALZHEIMER’S DISEASE AND NEURONS
Excessive buildup of glue-like substances
Gradually destroy neurons
Researchers can study a person’s mental activities by taking brain scans of the neural activities going on inside the living brain

16. ALZHEIMER’S DISEASE AND NEURONS

17. PARTS OF THE NEURON Cell body
Large egg-shaped structure that provides ______________________________________________________________________________________________________________________________
Dendrite
Branch-like extensions that arise from the cell body
____________________________________________________________________________________________
________________________________________________________________________________________________________________________________________________________________________________________

18. PARTS OF THE NEURON (CONT’D)
Axon
A single thread-like structure that extends/carries signals away from the cell body to neighboring neurons, organs, or muscles
Myelin sheath
Looks like separate tube-like segments composed of fatty material that wraps around and insulates an axon
______________________________________________________________________________________________________________________________

19. PARTS OF THE NEURON (CONT’D)
End bulbs or terminal bulbs
Located at extreme ends of the axon’s branches
Miniature container that ______________________________________________________________________________________________________________________________
Synapse
Infinitely small space (20-30 billionths of a meter)
Exists between an end bulb and its adjacent body organ, heart, muscles, or cell body

20. NEURONS VERSUS NERVES Reattaching limbs John Thomas
lost arms in farming accident
Transplanting a face
Isabelle
face severely disfigured by a dog
received
new nose
lips
chin

21. NERUONS VERSUS NERVES

22. PERIPHERAL & CENTRAL NERVOUS SYSTEM
Peripheral nervous system
Made up of nerves located throughout the body, ________________________________________________________________________________________________
Nerves
___________________________________ that come from the spinal cord and are held together by connective tissue
Carry information from the ________________________________________________________________________________________________
Those in the peripheral nervous system have the ability to grow or reattach if severed or damaged

23. PERIPHERAL & CENTRAL NERVOUS SYSTEM (CONT’D)
Made up of neurons located in the ____________________________________________________________________________________
Multiple sclerosis
________________________________________________________________________________________________________________________________________________________________________________________________________

24. SENDING INFORMATION: ACTION POTENTIAL SEQUENCE
Stimulus (tack or nail)
Skin has sensors that pick up mechanical pressure and transform it into electrical signals
Signals are sent by the neuron’s axon to various areas in the spinal cord and brain
Brain interprets electrical signals as “pain”
axon membrane has chemical gates that can open to allow electrically charged particles to enter or can close to keep out these particles
ions are chemical particles that have electrical charges
Opposite charges attract and like charges repel

25. SENDING INFORMATION: ACTION POTENTIAL SEQUENCE (CONT’D)

26. SENDING INFORMATION: ACTION POTENTIAL SEQUENCE (CONT’D)
Resting state
Axon has a charge
Charge results from the axon membrane separating ______________________________________________________________________________________________________________________________
Sodium pump
Transport process that picks up any sodium ions that enter the axon’s chemical gates and returns them back outside
Results in keeping axon charged by keeping sodium ions outside the axon membrane

27. SENDING INFORMATION: ACTION POTENTIAL SEQUENCE (CONT’D)
______________________________________________________________________________________________________________________________
Enormous __________ of sodium ions inside the axon causes the _______________to ___________ its charge
Inside becomes ____________ and outside becomes __________________

28. SENDING INFORMATION: NERVE IMPULSE

29. SENDING INFORMATION: NERVE IMPULSE (CONT’D)
Nerve impulse is made up of six action potentials, with the first occurring at the beginning of the axon
All-or-none law
If an action potential starts at the beginning of the axon, the action potential will continue at the same speed segment to segment to the very end of the axon

31. TRANSMITTERS
A transmitter is a chemical messenger that transmits information between nerves and body organs, such as muscles and heart
Excitatory and inhibitory
Excitatory transmitters (agonists)
________________________________________
Inhibitory transmitters (antagonists)

32. Agonists

33. Antagonists

34. NEUROTRANSMITTERS Neurotransmitters
Dozens of different chemicals made by ____________________________ and then used for ________________ between neurons during the performance of _____________________________________________________________________________ activities

35. NEUROTRANSMITTERS (CONT’D)

36. Acetylcholine (ACH)
Deals with motor movement and memory.
Too much and you will….
Too little and you will…
Lack of ACH has been linked to Alzheimer’s disease.

37. Dopamine
Deals with motor movement and alertness.
Lack of dopamine has been linked to Parkinson’s disease.
Too much has been linked to schizophrenia.

38. Serotonin
Involved in mood control.
Lack of serotonin has been linked to clinical depression.

39. ALCOHOL Alcohol (ethyl alcohol)
A ____________________________________, which means that it _____________________ the activity of the ____________________________________________________________________________________

40. ALCOHOL (CONT’D)

41. WHAT DOES ALCOHOL DO?
Alcohol affects the brain by imitating a naturally occurring neurotransmitter, GABA
GABA neurons
GABA neurons have chemical locks that can be opened by chemical keys in the form of the neurotransmitter GABA
GABA keys
Alcohol molecules so closely resemble those of the GABA neurotransmitter that alcohol can function like GABA keys and open GABA receptors
When GABA neurons are excited, they decrease neural activity

42. WHAT DOES ALCOHOL DO? (CONT’D)
Many people drink alcohol to feel less anxious and more relaxed
Appears to be a biological link between alcohol and anxiety
Deficiency in a specific brain protein is associated with high anxiety and excessive alcohol use

43. Neurotransmitters

44. NEW TRANSMITTERS Number of well-known neurotransmitters, such as
Norepinephrine
GABA
Dopamine
Serotonin

45. NEW TRANSMITTERS (CONT’D)
Endorphins (1970s)
painkiller similar to morphine
decreases effects of pain during great bodily stress
Anandamide (1990s)
similar to THC (active ingredient in marijuana)
involved with
memory
motor coordination
emotions

46. NEW TRANSMITTERS (CONT’D)
Anandamide may help people regulate emotions, which would help them to better deal with anxiety and stress
Nitric oxide (mid-1990s)
may be involved in regulating aggressive and impulsive behaviors

47. NEW TRANSMITTERS (CONT’D)
Orexin (hypocretin)
late 1990s
involved in the brain’s pleasure and reward system
high levels: ____________________________
low levels: ______________________________
involved in sleep and wakefulness
_____________________________________

48. REFLEX
Reflex
______________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________________________________________________________

49. REFLEX (CONT’D) Reflex sequence Sensors
________________________________________________________________________________________________________________________
Afferent neurons (sensory neurons)

50. REFLEX (CONT’D) Interneuron
relatively short neuron whose primary task is ________________________________________________________________________________________________________________________
Efferent neuron
________________________________to produce ____________________ in various muscles and organs throughout the body

51. REFLEX (CONT’D)

52. PARKINSON’S DISEASE Parkinson’s disease
Includes symptoms of tremors and shakes in the limbs, a slowing of voluntary movements, muscle stiffness, problems with balance and coordination, and feelings of depression
As the disease progresses, patients develop a shuffling walk and may suddenly freeze in space for minutes or hours at a time
Michael J. Fox

53. PARKINSON’S DISEASE (CONT’D)
Caused by destruction of neurons that produce dopamine
L-dopa is a medication that boosts the levels of dopamine in the brain
Eventually, the drug causes involuntary jerky movements
After prolonged use, L-dopa’s beneficial effect may be replaced by unwanted jerky movements

54. EXPERIMENTAL TREATMENTS
Sterotaxic procedure
Fixing a patient’s head in a holder and drilling a small hole through the skull
The holder has a syringe that can be precisely guided into a predetermined location in the brain

55. EXPERIMENTAL TREATMENTS (CONT’D)

56. EXPERIMENTAL TREATMENTS (CONT’D)

57. EXPERIMENTAL TREATMENTS (CONT’D)
Removing part of the brain
Thalamotomy (Michael J. Fox)
Brain stimulation
Electrodes placed into thalamus
Patient controls amount of stimulus
Helps reduce tremors

58. EXPERIMENTAL TREATMENTS (CONT’D)